Lets summarise it this way. Israel might survive for the next 50 years(ignoring PO and such), it will not survive in it's current format.
A short list of issues, which barely cover the major problems.
Water, Israel currently dumps like a third of it's water to Jordan(peace agreement), and it's rapidly running out. Reserves are not being met, and we'll need atleast three years straight of heavy rains to return to a safe situation[Haaretz].
Demographics, Israel is currently fighting a lame demographic fight(quiet Hash
) against the overbreeding of the arab population and Beduin...by counter over breeding. Thsi is not going to work. But does lead to the third problem.
Social divides. There exist, at least, 5 societies in Israel, which are, at best, cordial and at worst, open war. These are, in order of sanity, National Religious, Seculers, Arabs, Ultra-Orthodox, Beduin/other fringes.
Security, between a hostile population of Palestinians inside our borders, to hostile populations north/north-east/south-west, the situation is not good and the par is getting smaller every year.
And oh right, a social divide that threatens to break apart the system. Unlike the United States, we have a welfare system, and having it break might lead to...issues.